JACKSON, WY - Sulfur dioxide emitted from volcanoes and from burning fossil fuel is the primary initiator of global climate change, according to Dr. Peter L. Ward, a retired U.S. Geological Survey scientist who continues to study the earth and its environment through his own company, Teton Tectonics. "Carbon dioxide is a greenhouse gas compounding global warming, but it is not the initiator of climate change," according to Ward.

In a paper to be published this week, Ward concludes that sulfur dioxide emissions regulate the ability of the atmosphere to clean itself by oxidizing greenhouse gases. Sulfur dioxide reacts quickly with available oxidants, leaving few to react with other greenhouse gases. The primary oxidants, created by the effects of ultraviolet sunlight on ozone, are, like ozone, in limited supply.

Ward observed that the highest rates of global warming in the past 46,000 years occurred precisely when volcanoes were most active. "When very large volcanic eruptions occur every few months," Ward says, "rapid warming follows. Too much sulfur dioxide in a short period of time causes warming."

Large eruptions in the past 2000 years occurred once per century. Yet by 1962, human activities were putting as much sulfur dioxide into the atmosphere every 1.7 years as one of these large eruptions. That was enough to cause world temperatures to climb rapidly.

"By reducing acid rain, we accidentally reduced global warming," Ward said. "The problem now is that sulfur dioxide emissions are rapidly increasing again as new power plants come on line every week around the world. But we know how to reduce sulfur emissions both technically and politically. It is much easier to do than reducing carbon dioxide emissions."

Ward is holding a press conference at the Swissotel, Edelweiss Room, 323 E. Wacker Dr., Chicago on Wednesday, February 11 at 11 AM.

Ward's paper will be published in the next issue of "Thin Solid Films," a physics journal published by Elsevier Press, available online at www.sciencedirect.com/science/journal/00406090 (doi:10.1016/j.tsf.2009.01.005).

More details including Notes for Science Writers are found at Ward's website: www.tetontectonics.org.

Contact Peter Ward at 307-733-3664, cell 307-413-4055, or peward@wyoming.com. He will be available in Chicago February 11 though 15.

Global climate change prior to the 20th century, appears to primarily initiated by changes in vulcanic activity. Sulfur dioxide (SO2) is the most voluminous chemically active gas emitted by volcanoes and is readily oxidized to sulfuric acid normally within weeks. But trace amounts of SO 2 exert significant influence on climate. All major historic volcanic eruptions have formed sulfuric acid aerosols in the lower stratosphere that cooled the earth's surface ~0.5 o C for typically three years. While such events are currently happening once every 80 years, there are times in geologic history when they occurred every few to a dozen years. These were times when the earth was cooled incrementally into major ice ages. There have also been dozens of times during the past 46,000 years when major volcanic eruptions occurred every year or two or even several times per year for decades. Each of these times was contemporaneous with very rapid global warming. Large volumes of SO 2 erupted frequently overdrive the oxidizing capacity of the atmosphere resulting in very rapid warming. Such warming and associated acid rain becomes extreme when millions of cubic kilometers of basalt are erupted in much less than one million years. These are the times of the greatest mass extinctions. When major volcanic eruptions do not occur for decades to hundreds of years, the atmosphere can oxidize all pollutants, leading to a very thin atmosphere, global cooling and decadal drought. Prior to the 20th century, increases in atmospheric CO 2 followed increases in temperature initiated by changes in SO 2 .

By 1962, man burning fossil fuels was adding SO 2 to the atmosphere at a rate equivalent to one "large" volcanic eruption each 1.7 years. SO 2 is playing a far more active role in global warming than recognized by the Intergovernmental Panel on Climate Change. But man is also adding two to three orders of magnitude more CO 2 per year to the climate than one "large" volcanic eruption added in the past. Thus CO 2 , a greenhouse gas, is now also causing warming. Both SO 2 and CO 2 must be reduced to reduce global warming. We have already significantly reduced SO 2 emissions in order to reduce acid rain. We know how to do it both technically and politically.

In the past, sudden climate change was typically triggered by sudden increases in volcanic activity. Slow increases in greenhouse gases, therefore, do not appear as likely as currently thought to trigger tipping points where the climate suddenly changes.

How the Rate of Volcanism Initiated the Medieval Warm Period and Controlled Its Periods of Drought: Talk at the national meeting of the Geological Society of America in Houston, TX, October 6, 2008

Notes for Science Writers: The best place to start. PDF Public Lecture in Jackson, Wyoming on February 22, 2009 Holocene Concentrations of Methane in the Atmosphere are in Part Proportional to Concentrations of Sulfur Dioxide and Inversely Proportional to the Oxidizing Capacity of the Atmosphere: Poster at the fall meeting of the American Geophysical Union in San Francisco, CA, December 19, 2008